静动荷载作用下筋土界面作用模式与土工格栅加筋效应的宏细观研究

Due to the technical and cost advantages, geogrids have been widely used in various geogrid reinforced soil structures in practice. It is of great importance to investigate the geogrid-soil interaction mechanism in the design and application of geogrid reinforced soil structures. The current studies of geogrid-soil interface behavior are mainly carried out under static loads. Investigation results of geogrid reinforcement mechanisms under dynamic loads are quite rare. Therefore, geogrid pullout tests and large-scale geogrid reinforced soil retaining wall model tests will be carried out under static and dynamic loading conditions. The geogrid-soil interface behavior and geogrid reinforcing effects will be investigated comprehensively at the macroscopic level. Based upon the above macroscopic experimental results and the numerical simulation approach using the discrete element method (DEM), the corresponding DEM models will be established. The geogrid-soil interaction mechanisms will be illustrated in depth under static and dynamic loads at the macroscopic level. The load transfer behavior between geogrid and soil will be described and the mechanical response mechanisms of geogrid and soil particles will be established. Furthermore, the tensile force, displacement and strain developing laws of geogrids will be quantified. The investigation results of this study can improve the understanding of interaction mechanisms between geogrid and soil, which provides theoretical support for the design of geogrid reinforced soil structures.

土工格栅以其良好的技术与成本优势广泛应用于各类加筋土结构工程实践，探究土工格栅与土之间的相互作用机理在加筋土结构设计与应用中至关重要。现有的筋土界面作用机理的研究工作主要是在静荷载作用下进行的，关于动荷载边界条件下土工格栅加筋机理的研究成果鲜有报道。鉴于此，本项目将开展静动荷载边界条件下土工格栅拉拔试验以及大尺寸加筋土挡墙模型试验，从宏观层面系统探究土工格栅与土之间的界面作用模式以及土工格栅的加筋效应；基于上述宏观试验结果，依托离散元数值模拟方法，建立对应的离散元计算模型，从细观层面深入阐述静动荷载边界条件下土工格栅与土之间的相互作用机理，揭示土工格栅与土之间的荷载传递规律，构建土工格栅与土颗粒的力学响应机制，量化土工格栅张力、位移以及应变的发展变化规律。本项目研究成果将丰富和完善对筋土界面作用机理的认识，为优化加筋土结构设计提供理论支持。

土工格栅以其良好的技术与成本优势广泛应用于各类加筋土结构工程实践，探究土工格栅与土之间的相互作用机理在加筋土结构设计与应用中至关重要。现有的筋土界面作用机理的研究工作主要是在静荷载作用等简单边界条件下进行的，关于动荷载等复杂边界条件下土工格栅加筋机理的研究成果鲜有报道。鉴于此，本项目通过理论分析、室内试验、模型试验与离散元数值模拟系统研究，明确了法向应力大小、动荷载频率、刚性与柔性边界条件、筋材类型、拉拔速率、填土高度等因素对筋土界面相互作用的影响，开发了模拟复杂顶部边界条件的土工格栅拉拔试验及加筋土挡墙模型试验细观统计分析程序，实现了复杂条件下筋土界面荷载传递规律的可视化，量化了土工格栅与土的力学响应及变形行为，提出了新型加筋土挡墙结构型式，揭示了加筋土挡墙在填筑过程与静、动荷载作用下力学特性与变形行为演化规律。研究成果丰富并完善了对筋土界面作用机理与土工格栅加筋效应的认识，为优化加筋土结构设计提供了理论支持。